1. Field of the Disclosure
The present disclosure relates to a vacuum interrupter, and particularly, to a vacuum interrupter having enhanced performance of discharging air from the interior of a bellows in a breaking operation.
2. Background of the Disclosure
In general, a vacuum circuit breaker is a sort of circuit breaker is installed in a high voltage electric power system to break a circuit in a dangerous situation such as a short circuit or an overcurrent to protect the electric power system, which is designed by utilizing the fact that the vacuum circuit breaker has excellent insulating properties and arc extinguishing capability.
In the vacuum circuit breaker, a core component is a vacuum interrupter which performs a function of electrically connect a circuit or breaking the circuit within a hermetically sealed vacuum tube. The vacuum circuit breaker includes a fixed electrode and a movable electrode that can be brought into contact with the fixed electrode or separated from the fixed electrode. In particular, portions where the fixed electrode and the movable electrode are directly in contact with each other are called a fixed contact and a movable contact.
Here, in particular, since the movable electrode makes a linear movement so as to be brought into contact with the fixed electrode or separated from the fixed electrode, while the interior of the vacuum interrupter is maintained in a vacuum state, a bellows is installed around the movable electrode.
The interior of the vacuum interrupter is in a vacuum state, and atmospheric pressure or gas pressure is applied to the interior of the bellows. Since pressure of the gas applied to the interior of the bellows greatly affects operation characteristics of the vacuum interrupter, an influence of gas pressure should be taken into consideration in designing a manipulator or determining capacity. When gas pressures is increased, a self-closing force of the vacuum interrupter is increased to cause an increase in a speed in a closing operation and cause a decrease in a speed in a breaking operation, and thus, performance of the manipulator should be increased.
FIG. 1 illustrates an internal structure of a vacuum interrupter according to a related art. In the vacuum interrupter 100 according to the related art, a fixed contact 1, a fixed electrode 2, a movable contact 3, a movable electrode 5, a bellows 6, and a bellows guide 7 are installed within an enclosure formed of a ceramic container 5, an upper fixing unit flange 8, and a lower moving unit flange 9. Here, the interior of the enclosure is maintained in a vacuum state.
The fixed contact 1 and the fixed electrode 2 connecting the fixed contact 1 to a power source or a load outside of the vacuum interrupter 100 are connected to each other, and the fixed electrode 2 is connected such that it is sealed by the fixing unit flange 8.
The movable contact 3 facing the fixed contact 1 is connected to the movable electrode 4, and the movable electrode 4 is connected to a load or a power source outside of the vacuum interrupter 100. Here, the bellows 6 is installed on the movable contact 4 such that the bellows 6 can be freely moved while maintaining the vacuum state inside the vacuum interrupter 100.
The bellows guide 7 is installed between the movable electrode 4 and the bellows 6 and is fixed to be installed in the moving unit flange 9. The bellows guide 7 assists the movable electrode 4 to make a reciprocal linear movement, prevents the movable electrode 4 from being shaken to the side when making a linear movement, and enables air or a gas inside A the bellows to be discharged to the outside.
FIG. 2 illustrates a detailed structure of the bellows guide 7 according to the related art. An inner surface 7a of the bellows guide 7 is in contact with an outer surface of the movable electrode 4, and an outer surface 7b of the bellows guide 7 is installed to face an inner side of the bellows 6. Also, a protrusion 7c of the bellows guide 7 is inserted into a groove (not shown) of the movable electrode 4, guides the movable electrode 4 to make a linear movement, and is provided to prevent the movable electrode 4 from staggering to deform and damage the bellows 6.
When the vacuum interrupter 100 performs a breaking operation, the bellows 6 is compressed, and here, the groove 7d formed inside of the bellows guide 7 functions as an exit for discharging air or a gas inside A of the bellows 6 to the outside.
In the vacuum interrupter 100 according to the related art, when the bellows 6 performs a breaking operation, air or a gas inside A of the bellows 6 is discharged to the outside through the groove 7d formed in a length direction inside of the bellows guide 7.
However, when a breaking speed is fast or a gas pressure inside A of the s bellows 6 is increased, the exit of the groove 7d cannot tolerate an amount of outflow gas which is rapidly expanded, to result in an incomplete operation or to become slow in a breaking speed. In addition, since the groove 7d is formed in a narrow space between the bellows guide 7 and the movable electrode 4, there is a limitation in securing a sufficient space.